U.S. patent application number 13/226031 was filed with the patent office on 2013-03-07 for pin fin arrangement for heat shield of gas turbine engine.
The applicant listed for this patent is Honza Stastny, Robert Sze, Jeffrey VERHIEL. Invention is credited to Honza Stastny, Robert Sze, Jeffrey VERHIEL.
Application Number | 20130055722 13/226031 |
Document ID | / |
Family ID | 47752085 |
Filed Date | 2013-03-07 |
United States Patent
Application |
20130055722 |
Kind Code |
A1 |
VERHIEL; Jeffrey ; et
al. |
March 7, 2013 |
PIN FIN ARRANGEMENT FOR HEAT SHIELD OF GAS TURBINE ENGINE
Abstract
A heat shield unit for a gas turbine engine combustor comprises
a panel body secured to a combustor liner. A first surface of the
body is oriented toward a combustion zone of a combustor. A second
surface is oriented toward the liner. The body is separated into
upstream and downstream portions. Pin fins project from the second
surface of the body. The pin fins are arranged in arrays of at
least two different densities of volume of pin fins per unit
volume. One density, lower than the second density, is in the
upstream portion and another in the downstream portion of the body.
Connectors connect the body to the liner with a line between the
upstream and downstream portions of the body aligned with
fluid-coolant injection apertures in the liner. A gas turbine
engine combustor and a method for cooling a heat shield unit in a
combustor liner of a gas turbine engine are also provided.
Inventors: |
VERHIEL; Jeffrey; (Toronto,
CA) ; Stastny; Honza; (Georgetown, CA) ; Sze;
Robert; (Mississauga, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VERHIEL; Jeffrey
Stastny; Honza
Sze; Robert |
Toronto
Georgetown
Mississauga |
|
CA
CA
CA |
|
|
Family ID: |
47752085 |
Appl. No.: |
13/226031 |
Filed: |
September 6, 2011 |
Current U.S.
Class: |
60/772 ;
60/752 |
Current CPC
Class: |
F23R 3/60 20130101; F23R
2900/03042 20130101; F23R 3/007 20130101; F23R 2900/03044 20130101;
Y02T 50/675 20130101; Y02T 50/60 20130101; F23R 3/06 20130101 |
Class at
Publication: |
60/772 ;
60/752 |
International
Class: |
F02C 7/24 20060101
F02C007/24 |
Claims
1. A heat shield unit for a gas turbine engine combustor,
comprising: a panel body adapted to be secured to a combustor
liner, the panel body having a first surface adapted to be oriented
toward a combustion zone of a combustor, and a second surface
adapted to be oriented toward the combustor liner, the panel body
being separated in an upstream portion and a downstream portion;
pin fins projecting from the second surface of the panel body, the
pin fins being arranged in arrays of at least two different
densities of volume of pin fins per unit volume, with one said
densities in the upstream portion and another said densities in the
downstream portion of the panel body, with a first density of the
at least two different densities being lower than a second density
of the at least two different densities; and connectors to connect
the panel body to the combustor liner with a line between the
upstream portion and the downstream portion of the panel body being
aligned with fluid-coolant injection apertures in the combustor
liner.
2. The heat shield unit according to claim 1, wherein at least some
of the pin fins in the second density are taller than at least some
of the pin fins in the first density.
3. The heat shield unit according to claim 1, wherein at least some
adjacent ones of the pin fins in the first density are spaced apart
farther than that at least some adjacent ones of the pin fins in
the first density.
4. The heat shield unit according to claim 1, wherein at least some
of the pin fins in one of the densities have a greater sectional
size than at least some of the pin fins in the other of the
densities.
5. The heat shield unit according to claim 1, wherein the pin fins
are cylinders.
6. The heat shield unit according to claim 1, wherein the
connectors are posts projecting from the second surface.
7. A gas turbine engine combustor, comprising: a combustor liner
defining a combustion volume, with apertures in the combustor liner
for insertion of coolant fluid in the combustion volume; at least
one heat shield unit comprising: a panel body secured to the
combustor liner, the panel body having a first surface oriented
toward the combustion zone, and a second surface oriented toward
the combustor liner; pin fins projecting from the second surface of
the panel body, the pin fins being arranged in arrays of at least
two different densities of volume of pin fins per unit volume, with
a first density of the at least two different densities being lower
than a second density of the at least two different densities, with
the panel body positioned relative to the apertures of the
combustor liner for a location of the pin fins between the at least
two densities to receive the coolant fluid; and connectors to
connect the panel body to the combustor liner.
8. The gas turbine engine combustor according to claim 7, wherein
at least some of the pin fins in the second density are taller than
at least some of the pin fins in the first density.
9. The gas turbine engine combustor according to claim 7, wherein
at least some adjacent ones of the pin fins in the first density
are spaced apart farther than that at least some adjacent ones of
the pin fins in the first density.
10. The gas turbine engine combustor according to claim 7, wherein
at least some of the pin fins in one of the densities have a
greater sectional size than at least some of the pin fins in the
other of the densities.
11. The gas turbine engine combustor according to claim 7, wherein
the pin fins are cylinders.
12. The gas turbine engine combustor according to claim 7, wherein
the connectors are posts projecting from the second surface.
13. The gas turbine engine combustor according to claim 7,
comprising at least two of said heat shield units, with the panel
bodies of the heat shield units being adjacent and offset from one
another, such that the coolant fluid portion exiting from passing
through the pin fins of one of the heat shield units film cools the
first surface of the other of the heat shield units.
14. The gas turbine engine combustor according to claim 7, wherein
the pin fins opposite to the apertures are in an array of lower
density than adjacent arrays of pin fins.
15. The gas turbine engine combustor according to claim 7, wherein
the pin fins opposite to the apertures are in smaller than adjacent
pin fins.
16. A method for cooling a heat shield unit in a combustor liner of
a gas turbine engine, the heat shield unit secured to the combustor
liner and defining a gap therewith with pin fins projecting from
the heat shield unit toward the combustor liner in the gap, the
method comprising: injecting coolant fluid into the gap through
apertures in the combustor liner; directing a first portion of said
coolant fluid in a first direction through a first array of the pin
fins; and directing a second portion of said coolant fluid in a
second direction through a second array of the pin fins, the second
portion of said coolant fluid having a greater volumetric flow
value than that of the first portion of said coolant fluid by
having a density of pin fins per unit volume in the second array
different than a density of pin fins per unit volume in the first
array.
17. The method according to claim 16, further comprising directing
at least one of the first portion and the second portion of coolant
fluid beyond an edge of one of the heat shield units to film cool a
surface of an adjacent heat shield unit.
Description
TECHNICAL FIELD
[0001] The present application pertains to aircraft gas turbine
engines and, more particularly, to heat shields found in a
combustor of the gas turbine engine and to a pin fin arrangement of
such a heat shield for cooling purposes.
BACKGROUND OF THE ART
[0002] In gas turbine engines, the combustor performance directly
impacts the overall fuel efficiency of the gas turbine engine and
the pollutant emission. Heat shields, also known as float walls,
have therefore been provided within combustors to allow the
combustor to operate at higher temperatures with relatively low
combustor pressure drops. As a result, the specific field
consumption of gas turbine engines is enhanced.
[0003] For cooling purposes, the heat shields may be equipped with
a plurality of pin fins oriented away from the combustion zone of
the combustor. A coolant fluid circulates between the pin fins,
thereby cooling the heat shields. Spent coolant fluid is then
directed onto the exposed surface of the heat shields to perform
film cooling. The fluid coolants are therefore used for two
different types of cooling, namely internally through the pin array
and externally via film cooling.
[0004] Fresh coolant fluid is introduced where film cooling
effectiveness dies. Accordingly, coolant fluid introduction has an
impact on the axial length of the heat shields. To ensure optimal
coolant distribution, some circumferential rails and like
deflectors have been added among pin fin arrays. However, such
rails may introduce undesirable extra contact points, extra hot
spots and stiffness discontinuity and this may have an impact on
the overall durability of the heat shields.
SUMMARY
[0005] According to a first embodiment, there is provided a heat
shield unit for a gas turbine engine combustor, comprising: a panel
body adapted to be secured to a combustor liner, the panel body
having a first surface adapted to be oriented toward a combustion
zone of a combustor, and a second surface adapted to be oriented
toward the combustor liner, the panel body being separated in an
upstream portion and a downstream portion; pin fins projecting from
the second surface of the panel body, the pin fins being arranged
in arrays of at least two different densities of volume of pin fins
per unit volume, with one said densities in the upstream portion
and another said densities in the downstream portion of the panel
body, with a first density of the at least two different densities
being lower than a second density of the at least two different
densities; and connectors to connect the panel body to the
combustor liner with a line between the upstream portion and the
downstream portion of the panel body being aligned with
fluid-coolant injection apertures in the combustor liner.
[0006] According to a second embodiment, there is provided a gas
turbine engine combustor, comprising: a combustor liner defining a
combustion volume, with apertures in the combustor liner for
insertion of coolant fluid in the combustion volume; and at least
one heat shield unit comprising a panel body secured to the
combustor liner, the panel body having a first surface oriented
toward the combustion zone, and a second surface oriented toward
the combustor liner, pin fins projecting from the second surface of
the panel body, the pin fins being arranged in arrays of at least
two different densities of volume of pin fins per unit volume, with
a first density of the at least two different densities being lower
than a second density of the at least two different densities, with
the panel body positioned relative to the apertures of the
combustor liner for a location of the pin fins between the at least
two densities to receive the coolant fluid, and connectors to
connect the panel body to the combustor liner.
[0007] According to a third embodiment, there is provided a method
for cooling a heat shield unit in a combustor liner of a gas
turbine engine, the heat shield unit secured to the combustor liner
and defining a gap therewith with pin fins projecting from the heat
shield unit toward the combustor liner in the gap, the method
comprising: injecting coolant fluid into the gap through apertures
in the combustor liner; directing a first portion of said coolant
fluid in a first direction through a first array of the pin fins;
and directing a second portion of said coolant fluid in a second
direction through a second array of the pin fins, the second
portion of said coolant fluid having a greater volumetric flow
value than that of the first portion of said coolant fluid by
having a density of pin fins per unit volume in the second array
different than a density of pin fins per unit volume in the first
array.
DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of a gas turbine engine,
featuring heat shield units in accordance with an embodiment of the
present disclosure;
[0009] FIG. 2 is a sectional view of a combustor of the gas turbine
engine of FIG. 1, with the heat shield units of the present
disclosure;
[0010] FIG. 3 is a sectional view of the combustor with heat shield
units of FIG. 2, showing a flow of cooling air; and
[0011] FIG. 4 is a perspective view of one of the heat shield units
of FIG. 2, showing a pin fin distribution.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] FIG. 1 illustrates a turbofan gas turbine engine 10 of a
type preferably provided for use in subsonic flight, generally
comprising in serial flow communication a fan 12 through which
ambient air is propelled, a multistage compressor 14 for
pressurizing the air, a combustor 16 in which the compressed air is
mixed with fuel and ignited for generating an annular stream of hot
combustion gases. Jet nozzles are illustrated at 17 relative to the
combustor 16. A turbine section 18 extracts energy from the
combustion gases.
[0013] Referring to FIG. 2, a section of the combustor 16 is
generally illustrated. The combustor 16 has a combustor liner 20
mounted about the fuel nozzle 17 and projecting downstream from the
fuel nozzle 17. Therefore, the combustor liner 20 defines an inner
volume in which combustion occurs (i.e., combustion zone). Jet
apertures 21 (i.e., jets) are defined in various locations of the
combustor liner 20, for the insertion of coolant fluid in the
combustor 16. The jets 21 may be used to provide coolant fluid to
heat shields mounted onto the combustor liner 20. Connection bores
22 are provided in the combustor liner 20. The connection bores 22
may be used to anchor the heat shields to the combustor liner 20.
The combustor liner 20 may feature offsetting sections 23 to form a
step-like shape to the combustor liner 20 in a downstream
direction.
[0014] Referring concurrently to FIGS. 2 and 3, a plurality of heat
shield units 30 are shown as being secured to the combustor liner
20. The heat shield units 30 may also be known as float walls, etc.
It is pointed out that in FIGS. 2 and 3, the numerous heat shield
units 30 and components thereof have reference numerals affixed
with an A, B, etc, to be individually identified for subsequent
description of the flow of coolant fluid. However, reference will
be made in the text to the heat shield units 30 and components
without affixed letters unless the description is specific to a
given heat shield unit 30.
[0015] The heat shield units 30 each have a panel body with a first
surface 31 and a second surface 32. The panel body is railless,
i.e., it does not feature rails or like elongated member extending
on the surfaces 31 and 32. The first surface is relatively smooth
and continuous and is oriented internally relative to the combustor
16, i.e., faces the combustion zone. The second surface 32
therefore faces toward the combustor liner 20.
[0016] Connector posts 33 project from the second surface 32 of the
heat shield units 30. The connector posts 33 are spaced apart from
one another to be in register with the connection bores 22 in the
combustor liner 20. Accordingly, when the heat shield units 30 are
anchored to the combustor liner 20, the connector posts 33 are
threaded through the connection bores 22.
[0017] Fasteners 34 (e.g., nuts, washers, rings, etc) are
operatively connected to the connector posts 33 so as to releasably
fix the heat shield units 30 to the combustor liner 20. Free ends
of the connector posts 33 and the fasteners 34 therefore project
outside of the combustor liner 20 (e.g., in the plenum of the gas
turbine engine).
[0018] Any other connection means may be used to secure the heat
shield units 30 to the combustor liner 20, including blots, tabs,
brackets, etc.
[0019] Referring concurrently to FIGS. 2 to 4, pin fins are
illustrated as 35. The pin fins 35 are arranged in arrays of
multiple pin fins (as best seen in FIG. 4), whereby only a few of
the pin fins are actually labeled, to simplify the illustrations.
The pin fins 35 are illustrated as having a circular section.
However, any other appropriate shape of pin fins 35 is considered.
In FIG. 4, the pin fins 35 are shown forming to different zones,
each zone regrouping similar pin fins 35. As shown in zone Z1, the
pin fins 35 have a same diameter, height and are spaced apart
evenly, thereby defining a first density of pin fins (e.g., pin fin
volume per total volume unit, pin fin area per total surface unit).
As seen in zone Z2, some fins adjacent to the fins of zone Z1 may
be spaced apart further than the pin fins of zone Z1. Accordingly,
the density of pin fins in zone Z2 is lower than that of zone Z1.
Fuel coolant circulation is enhanced when the pin fin density is
lower.
[0020] Moreover, according to another embodiment, the pin fins of
zone Z1 are shown having a greater height than the pin fins of zone
Z2, causing a lower volume density of fins in zone Z2. Again, the
array of pin fins within zone Z2 causes less restriction of flow
than that of zone Z1, because of the reduced height. The array of
pin fins of zone Z2 is particularly well suited to be opposite the
jets 21 to allow coolant to flow into the combustor 16 from the
adjacent plenum. FIGS. 2 and 3 therefore show shorter pin fins 35
opposite the jets 21.
[0021] In zone Z3, there are pin fins with a diameter greater than
that of zone Z1 or Z2. The arrangement of zone Z3 is therefore of
lesser density than that of zone Z1, thereby causing less flow
restriction. The larger pin fins may be less efficient in terms of
cooling efficient. However, zone Z3 is adjacent to connector posts
33 which may act as heats sink to cool the heat shield units
30.
[0022] Accordingly, FIG. 4 shows that the pin fins 35 on the second
surface 32 of the heat shield units 30 may be arranged in different
ways to alter the density of pin fins on the second surface 32 of
the heat shield units 30. The density of pin fins of a heat shield
30 is therefore selected to dictate the flow of coolant fluid, with
a volumetric flow value of the coolant fluid (e.g., cubic feet per
minute) being greater if the density of pin fins is smaller. An
example thereof is illustrated in FIG. 3. A coolant fluid from the
plenum is shown entering the combustor 16, at F1. With specific
reference to the heat shield unit 30A, a portion of the fluid F1 is
directed along a downstream portion of the heat shield unit 30A as
shown by direction F2. Therefore, the coolant fluid flows
downstream of a trailing edge 36A of the heat shield unit 30A to
film cool the heat shield unit 30B. A second portion of the coolant
fluid F1 is directed along an upstream portion of the heat shield
unit 30A as shown as F3. The coolant fluid F3 travels upstream and
beyond the leading edge 37A of the heat shield unit 30A to then
film cool the heat shield unit 30A, as shown by F4. To perform the
above-referred distribution of fluid flow, the pin fin arrays
upstream of the jets 21 associated with the heat shield unit 30A
may be of a smaller density than the pin fins downstream of these
jets 21. The heat shield unit 30A must therefore be installed with
the jets 21 being aligned with a line separating the upstream
portion from the downstream portion of the heat shield unit
30A.
[0023] Similarly, coolant fluid F1 entering the jets 21 opposite
the heat shield unit 30B moves upstream according to direction F3,
at which point the coolant fluid may be used to film cool the heat
shield unit 30B, by passing beyond leading edge 37B, while a
portion of the coolant fluid flows in direction F2, to film cool
the downstream heat shield unit 30, etc.
[0024] Therefore, the flow of coolant fluid is split using a
pressure differential induced by providing varying pin fin
resistance, by selecting appropriate densities of pin fins. The pin
fins 35 may have any pin height, diameter, section size, shape,
etc. to affect the density and cause such flow restrictions to
induce the appropriate pressure differential to dictate the flow of
coolant fluid.
* * * * *